Off-road bikes get dirty much faster than road bikes. A single ride with any moisture on the ground will likely coat the bike in mud.
Cleaning video guides
Stand, folding, aluminum: https://www.parktool.com/product/team-issue-repair-stand-prs-25
Degreaser, Simple Green, concentrated: http://a.co/d/7iFBobp
Clean at the trail vs clean at home?
I transport the bike inside our Honda Element (floor is hard plastic floor, but not hose-able.) Brush to knock off most of the mud, then a tarp to contain the rest, and a thorough wash at home.
Some people use a small hand pump sprayer to provide water. (It looks like that sprayer tank can also be used to seat tubeless tire beads.) Testing with a CamelBack shows that simply elevating an unpressurized container of water on top of the car provides enough head pressure to give a reasonable stream.